add matchLabels in Deployment yaml, that both API extensions/v1beta1 and apps/v1 can be used (#2036)

Signed-off-by: LinWengang <linwengang@chinacloud.com.cn>

deploy/default-backend.yaml

@@ -7,6 +7,9 @@ metadata:
   namespace: ingress-nginx
 spec:
   replicas: 1
+  selector:
+    matchLabels:
+      app: default-http-backend
   template:
     metadata:
       labels:

docs/examples/customization/external-auth-headers/deploy/auth-service.yaml

@@ -7,6 +7,9 @@ metadata:
   namespace: default
 spec:
   replicas: 1
+  selector:
+    matchLabels:
+      k8s-app: demo-auth-service
   template:
     metadata:
       labels:

docs/examples/customization/external-auth-headers/deploy/echo-service.yaml

@@ -7,6 +7,9 @@ metadata:
   namespace: default
 spec:
   replicas: 1
+  selector:
+    matchLabels:
+      k8s-app: demo-echo-service
   template:
     metadata:
       labels:

docs/examples/http-svc.yaml

@@ -4,6 +4,9 @@ metadata:
   name: http-svc
 spec:
   replicas: 1
+  selector:
+    matchLabels:
+      app: http-svc
   template:
     metadata:
       labels:

docs/examples/static-ip/nginx-ingress-controller.yaml

@@ -6,6 +6,9 @@ metadata:
     k8s-app: nginx-ingress-controller
 spec:
   replicas: 1
+  selector:
+    matchLabels:
+      k8s-app: nginx-ingress-controller
   template:
     metadata:
       labels:

images/echoheaders/echo-app.yaml

@@ -22,6 +22,9 @@ metadata:
     app: echoheaders
 spec:
   replicas: 1
+  selector:
+    matchLabels:
+      app: echoheaders
   template:
     metadata:
       labels: